As is well known in the art, valves are used throughout industry, including the railroad industry, for controlling fluid flow and fluid pressures provided by a source of such fluid flow and fluid pressures such as pumps and compressors. Fluid flow and fluid pressures are conducted through such control valves and through conduits (piping, tubing and hoses) connected to these control valves.
Valve construction varies, as is equally well known, but all fluid control valves have housings and require seats against which valve members abut to block fluid flow and cut-off fluid pressure, and which disengage the seats to allow and control fluid flow and fluid pressure directed through the valves.
Current practice involves the machining of a seat in the valve body. Such machining process is costly and can give rise to valve failures due to porosity which may be present in the cast material of the valve body and nicks in the seat area caused by machining tools.
Another costly process involves press fitting a bushing seat into place in the hollow of the valve body. This practice provides a more robust seat structure but it can lead to detrimental interior fluid leakage between the pressed fitting and the valve body. The press fitting used in this process is typically machined from bar stock.